Genetic tests, including prenatal testing, are available for both confirmed forms. Molecular testing is considered the gold standard of diagnosis.

Testing at pregnancy to determine whether an unborn child is affected is possible if genetic testing in a family has identified a DMPK mutation. This can be done at 10–12 weeks gestation by a procedure called chorionic villus sampling (CVS) that involves removing a tiny piece of the placenta and analyzing DNA from its cells. It can also be done by amniocentesis after 14 weeks gestation by removing a small amount of the amniotic fluid surrounding the baby and analyzing the cells in the fluid. Each of these procedures has a small risk of miscarriage associated with it and those who are interested in learning more should check with their doctor or genetic counselor.

There is also another procedure called preimplantation diagnosis that allows a couple to have a child that is unaffected with the genetic condition in their family. This procedure is experimental and not widely available. Those interested in learning more about this procedure should check with their doctor or genetic counselor.

A diagnosis of choroideremia can be made based on family history, symptoms, and the characteristic appearance of the fundus. However, choroideremia shares several clinical features with retinitis pigmentosa, a similar but broader group of retinal degenerative diseases, making a specific diagnosis difficult without genetic testing. Because of this choroideremia is often initially misdiagnosed as retinitis pigmentosa. A variety of different genetic testing techniques can be used to make a differential diagnosis.

It is possible to test someone who is at risk for developing DM1 before they are showing symptoms to see whether they inherited an expanded trinucleotide repeat. This is called predictive testing. Predictive testing cannot determine the age of onset that someone will begin to have symptoms, or the course of the disease. If the child is not having symptoms, the testing is not possible with an exception of emancipated minors as a policy.

The fundus exam via ophthalmoscopy is essentially normal early on in cone dystrophy, and definite macular changes usually occur well after visual loss. Fluorescein angiography (FA) is a useful adjunct in the workup of someone suspected to have cone dystrophy, as it may detect early changes in the retina that are too subtle to be seen by ophthalmoscope. For example, FA may reveal areas of hyperfluorescence, indicating that the RPE has lost some of its integrity, allowing the underlying fluorescence from the choroid to be more visible. These early changes are usually not detected during the ophthalmoscopic exam.

The most common type of macular lesion seen during ophthalmoscopic examination has a bull’s-eye appearance and consists of a doughnut-like zone of atrophic pigment epithelium surrounding a central darker area. In another, less frequent form of cone dystrophy there is rather diffuse atrophy of the posterior pole with spotty pigment clumping in the macular area. Rarely, atrophy of the choriocapillaris and larger choroidal vessels is seen in patients at an early stage. The inclusion of fluorescein angiography in the workup of these patients is important since it can help detect many of these characteristic ophthalmoscopic features. In addition to the retinal findings, temporal pallor of the optic disc is commonly observed.

As expected, visual field testing in cone dystrophy usually reveals a central scotoma. In cases with the typical bull’s-eye appearance, there is often relative central sparing.

Because of the wide spectrum of fundus changes and the difficulty in making the diagnosis in the early stages, electroretinography (ERG) remains the best test for making the diagnosis. Abnormal cone function on the ERG is indicated by a reduced single-flash and flicker response when the test is carried out in a well-lit room (photopic ERG). The relative sparing of rod function in cone dystrophy is evidenced by a normal scotopic ERG, i.e. when the test is carried out in the dark. In more severe or longer standing cases, the dystrophy involves a greater proportion of rods with resultant subnormal scotopic records. Since cone dystrophy is hereditary and can be asymptomatic early on in the disease process, ERG is an invaluable tool in the early diagnosis of patients with positive family histories.

Cone dystrophy in general usually occurs sporadically. Hereditary forms are usually autosomal dominant, and instances of autosomal recessive and X-linked inheritance also occur.

In the differential diagnosis, other macular dystrophies as well as the hereditary optic atrophies must be considered. Fluorescent angiography, ERG, and color vision tests are important tools to help facilitate diagnosis in early stages.

An accurate diagnosis of retinitis pigmentosa relies on the documentation of the progressive loss photoreceptor cell function, confirmed by a combination of visual field and visual acuity tests, fundus and optical coherence imagery, and electroretinography (ERG),

Visual field and acuity tests measure and compare the size of the patient's field of vision and the clarity of their visual perception with the standard visual measurements associated with healthy 20/20 vision. Clinical diagnostic features indicative of retinitis pigmentosa include a substantially small and progressively decreasing visual area in the visual field test, and compromised levels of clarity measured during the visual acuity test. Additionally, optical tomography such as fundus and retinal (optical coherence) imagery provide further diagnostic tools when determining an RP diagnosis. Photographing the back of the dilated eye allows the confirmation of bone spicule accumulation in the fundus, which presents during the later stages of RP retinal degeneration. Combined with cross-sectional imagery of optical coherence tomography, which provides clues into photoreceptor thickness, retinal layer morphology, and retinal pigment epithelium physiology, fundus imagery can help determine the state of RP progression.

While visual field and acuity test results combined with retinal imagery support the diagnosis of retinitis pigmentosa, additional testing is necessary to confirm other pathological features of this disease. Electroretinography (ERG) confirms the RP diagnosis by evaluating functional aspects associated with photoreceptor degeneration, and can detect physiological abnormalities before the initial manifestation of symptoms. An electrode lens is applied to the eye as photoreceptor response to varying degrees of quick light pulses is measured. Patients exhibiting the retinitis pigmentosa phenotype would show decreased or delayed electrical response in the rod photoreceptors, as well as possibly compromised cone photoreceptor cell response.

The patient's family history is also considered when determining a diagnosis due to the genetic mode of inheritance of retinitis pigmentosa. At least 35 different genes or loci are known to cause "nonsyndromic RP" (RP that is not the result of another disease or part of a wider syndrome). Indications of the RP mutation type can be determine through DNA testing, which is available on a clinical basis for:

- (autosomal recessive, Bothnia type RP)

- (autosomal dominant, RP1)

- (autosomal dominant, RP4)

- (autosomal dominant, RP7)

- (autosomal dominant, RP13)

- (autosomal dominant, RP18)

- CRB1 (autosomal recessive, RP12)

- (autosomal recessive, RP19)

- (autosomal recessive, RP20)

For all other genes (e.g. DHDDS), molecular genetic testing is available on a research basis only.

RP can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. X-linked RP can be either recessive, affecting primarily only males, or dominant, affecting both males and females, although males are usually more mildly affected. Some digenic (controlled by two genes) and mitochondrial forms have also been described.

Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing.

In terms of diagnosis of Fukuyama congenital muscular dystrophy, serum creatine kinase concentration and muscle biopsies can be obtained to help determine if the individual has FMCD. FKTN molecular genetic testing is used to determine a mutation in the FKTN gene after a serum creatine kinase concentration, muscle biopsies, and/or MRI imaging have presented abnormalities indicative of FCMD, the presence of the symptoms indicates Fukuyama congenital muscular dystrophy. The available genetic test include:

- Linkage analysis

- Deletion analysis

- Sequence analysis - exons

- Sequence analysis - entire coding region

Oguchi's disease is unique in its electroretinographic responses in the light- and dark-adapted conditions. The A- and b-waves on single flash electroretinograms (ERG) are decreased or absent under lighted conditions but increase after prolonged dark adaptation. There are nearly undetectable rod b waves in the scotopic 0.01 ERG and nearly negative scotopic 3.0 ERGs.

Dark-adaptation studies have shown that highly elevated rod thresholds decrease several hours later and eventually result in a recovery to the normal or nearly normal level.

The S, M and L cone systems are normal.

For the diagnosis of congenital muscular dystrophy, the following tests/exams are done:

- Lab study (CK levels)

- MRI (of muscle, and/or brain)

- EMG

- Genetic testing

In terms of the diagnosis of Ullrich congenital muscular dystrophy upon inspection follicular hyperkeratosis, may be a dermatological indicator, additionally also serum creatine kinase may be mildly above normal. Other exams/methods to ascertain if the individual has Ullrich congenital muscular dystrophy are:

The subtypes of congenital muscular dystrophy have been established through variations in multiple genes. It should be noted that phenotype, as well as, genotype classifications are used to establish the subtypes, in some literature.

One finds that congenital muscular dystrophies can be either autosomal dominant or autosomal recessive in terms of the inheritance pattern, though the latter is much more common

Individuals who suffer from congenital muscular dystrophy fall into one of the following "types":

Phototherapeutic keratectomy (PTK) done by an ophthalmologist can restore and preserve useful visual function for a significant period of time in patients with anterior corneal dystrophies including EBMD.

The diagnosis of Reis-Bücklers corneal dystrophy is based on the clinical presentation, rather than labs or imaging. Sometimes it is difficult to distinguish the disease from honeycomb dystrophy.

The diagnosis of oculopharyngeal muscular dystrophy can be done via two methods, a muscle biopsy or a blood draw with genetic testing for GCG trinucleotide expansions in the PABPN1 gene. The genetic blood testing is more common.Additionally, a distinction between OPMD and myasthenia gravis or mitochondrial myopathy must be made, in regards to the differential diagnosis of this condition.

Granular corneal dystrophy is diagnosed during an eye examination by an ophthalmologist or optometrist. The lesions consist of central, fine, whitish granular lesions in the cornea. Visual acuity is slightly reduced.

In terms of the diagnosis of Becker muscular dystrophy symptom development resembles that of Duchenne muscular dystrophy. A physical exam indicates lack of pectoral and upper arm muscles, especially when the disease is unnoticed through the early teen years. Muscle wasting begins in the legs and pelvis, then progresses to the muscles of the shoulders and neck. Calf muscle enlargement (pseudohypertrophy) is quite obvious. Among the exams/tests performed are:

- Muscle biopsy

- Creatine kinase test

- Electromyography (shows that weakness is caused by destruction of muscle tissue rather than by damage to nerves.)

- Genetic testing

Though there is no treatment for Cone dystrophy, certain supplements may help in delaying the progression of the disease.

The beta-carotenoids, lutein and zeaxanthin, have been evidenced to reduce the risk of developing age related macular degeneration (AMD), and may therefore provide similar benefits to Cone dystrophy sufferers.

Consuming omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid) has been correlated with a reduced progression of early AMD, and in conjunction with low glycemic index foods, with reduced progression of advanced AMD, and may therefore delay the progression of cone dystrophy.

Corneal transplant is not needed except in very severe and late cases.

Light sensitivity may be overcome by wearing tinted glassess.

The diagnosis of limb-girdle muscular dystrophy can be done via muscle biopsy, which will show the presence of muscular dystrophy, and genetic testing is used to determine which type of muscular dystrophy a patient has. Immunohistochemical dystrophin tests can indicate a decrease in dystrophin detected in sarcoglycanopathies. In terms of sarcoglycan deficiency there can be variance (if α-sarcoglycan and γ-sarcoglycan are not present then there's a mutation in LGMD2D).

The 2014 "Evidence-based guideline summary: Diagnosis and treatment of limb-girdle and distal dystrophies" indicates that individuals suspected of having the inherited disorder should have genetic testing. Other tests/analysis are:

- High CK levels(x10-150 times normal)

- MRI can indicate different types of LGMD.

- EMG can confirm the myopathic characteristic of the disease.

- Electrocardiography (cardiac arrhythmias in LGMD1B can occur)

The progression of Becker muscular dystrophy is highly variable—much more so than Duchenne muscular dystrophy. There is also a form that may be considered as an intermediate between Duchenne and Becker MD (mild DMD or severe BMD).

Severity of the disease may be indicated by age of patient at the onset of the disease. One study showed that there may be two distinct patterns of progression in Becker muscular dystrophy. Onset at around age 7 to 8 years of age shows more cardiac involvement and trouble climbing stairs by age 20, if onset is around age 12, there is less cardiac involvement.

The quality of life for patients with Becker muscular dystrophy can be impacted by the symptoms of the disorder. But with assistive devices, independence can be maintained. People affected by Becker muscular dystrophy can still maintain active lifestyles.

While nothing currently can be done to stop or reverse the retinal degeneration, there are steps that can be taken to slow the rate of vision loss. UV-blocking sunglasses for outdoors, appropriate dietary intake of fresh fruit and leafy green vegetables, antioxidant vitamin supplements, and regular intake of dietary omega-3 very-long-chain fatty acids are all recommended.

One study found that a dietary supplement of lutein increases macular pigment levels in patients with choroideremia. Over a long period of time, these elevated levels of pigmentation could slow retinal degeneration. Additional interventions that may be needed include surgical correction of retinal detachment and cataracts, low vision services, and counseling to help cope with depression, loss of independence, and anxiety over job loss.

Progressive vision loss in any dog in the absence of canine glaucoma or cataracts can be an indication of PRA. It usually starts with decreased vision at night, or nyctalopia. Other symptoms include dilated pupils and decreased pupillary light reflex. Fundoscopy to examine the retina will show shrinking of the blood vessels, decreased pigmentation of the nontapetal fundus, increased reflection from the tapetum due to thinning of the retina, and later in the disease a darkened, atrophied optic disc. Secondary cataract formation in the posterior portion of the lens can occur late in the disease. In these cases diagnosis of PRA may require electroretinography (ERG). For many breeds there are specific genetic tests of blood or buccal mucosa for PRA.

Absent a genetic test, animals of breeds susceptible to PRA can be cleared of the disease only by the passage of time—that is, by living past the age at which PRA symptoms are typically apparent in their breed. Breeds in which the PRA gene is recessive may still be carriers of the gene and pass it on to their offspring, however, even if they lack symptoms, and it is also possible for onset of the disease to be later than expected, making this an imperfect test at best.

The "LGMD1" family is autosomal dominant, and the "LGMD2" family is autosomal recessive. Limb-girdle muscular dystrophy is explained in terms of gene, locus, OMIM and type as follows:

Fukuyama congenital muscular dystrophy has a poor prognosis. Most children with FCMD reach a maximum mobility at sitting upright and sliding. Due to the compounded effects of continually worsening heart problems, impaired mental development, problems swallowing and additional complications, children with FCMD rarely live through adolescence, the disorder proves fatal by age 20.

Patients may complain of severe problems with dry eyes, or with visual obscurations. It can also be asymptomatic, and only discovered because of subtle lines and marks seen during an eye exam.

EBMD is a bilateral anterior corneal dystrophy characterized by grayish epithelial fingerprint lines, geographic map-like lines, and dots (or microcysts) on slit-lamp examination. Findings are variable and can change with time. While the disorder is usually asymptomatic, up to 10% of patients may have recurrent corneal erosions, usually beginning after age 30; conversely, 50% of patients presenting with idiopathic recurrent erosions have evidence of this dystrophy.

Other conditions with similar appearing fundi include

- Cone dystrophy

- X-linked retinitis pigmentosa

- Juvenile macular dystrophy

These conditions do not show the Mizuo-Nakamura phenomenon.